A shed of that size is not really very heavy. Not when it comes to small jacks. They are rated for lifting tonnes. 2, 4, 5, 8, etc. Find a small cheap one, if you don't want to use the fulcrum idea.
Other then that, everyone else has already given you the best ideas. This is one of those go slow and think it through situations. As long as you are not trying to lift it more than a few inches at a time it should be fine.
And do it one corner at a time, or only one side at a time. Do not try to lift the whole thing up at once. You will just be asking for an accident. 600 lbs on and arm is going to do some damage.
Good luck.
Other then that, everyone else has already given you the best ideas. This is one of those go slow and think it through situations. As long as you are not trying to lift it more than a few inches at a time it should be fine.
And do it one corner at a time, or only one side at a time. Do not try to lift the whole thing up at once. You will just be asking for an accident. 600 lbs on and arm is going to do some damage.
Good luck.
